FNA: Epilobium saximontanum vs. Onagraceae tribe Epilobieae

	Epilobium saximontanum	Onagraceae tribe Epilobieae
	glandular willowherb, Rocky Mountain willowherb, Rocky Mountain willowweed, épilobe des rocheuses
Habit	Herbs usually with sessile, fleshy, underground turions, or sometimes thick, elongated shoots with dark, decussate scales.	Herbs, annual or perennial, sometimes suffrutescent.
Stems	erect, strict, terete, 4–55 cm, simple or well branched in age, subglabrous proximally to mixed strigillose and glandular puberulent distally, with raised strigillose lines decurrent from margins of petioles.
Leaves	opposite proximal to inflorescence, alternate and reduced distally, often ± appressed, usually subsessile, rarely petiole 1–3 mm, often clasping; blade obovate proximally to ovate, lanceolate, or narrowly elliptic distally, 1–5.5(–6.5) × 0.4–2(–2.4) cm, base rounded or obtuse, margins low denticulate, 9–30 teeth per side, veins ± conspicuous, 3–6 per side, apex subacute, surfaces subglabrous with strigillose margins; bracts much reduced.	opposite at least near base or throughout, alternate distally, or sometimes alternate throughout; stipules absent.
Inflorescences	erect, sometimes nodding in bud, racemes, sometimes sparsely branched.
Flowers	erect; buds 2–3.5 × 1.8–2.5 mm; pedicel 0–1 mm; floral tube 0.8–1.4 × 0.8–1.9 mm, ring of sparse spreading hairs at mouth inside; sepals sometimes flushed red, 1.2–3.5 × 0.6–1.4 mm, abaxial surface strigillose and sometimes mixed glandular puberulent; petals usually white, infrequently pink, 2.2–5(–7) × 1.7–3.2 mm, apical notch 0.4–1.5 mm; filaments usually cream, rarely light pink, those of longer stamens 2–3.5 mm, those of shorter ones 1–2 mm; anthers cream to light yellow, 0.3–0.8 × 0.3–0.5 mm; ovary 9–30 mm, densely strigillose and glandular puberulent; style cream or yellow, 1.6–2.8 mm, stigma usually narrowly to broadly clavate, rarely subcapitate, 1–3 × 0.8–2 mm, surrounded by at least longer anthers.	actinomorphic or slightly zygomorphic, 4-merous; sepals erect or spreading; stamens 2 times as many as sepals; pollen shed in tetrads or monads.
Fruit		a slender, cylindrical, loculicidal capsule.
Capsules	30–55(–70) mm, surfaces mixed strigillose and glandular puberulent; usually subsessile, rarely pedicel 1–5 mm, often appressed to stem.
Seeds	very narrowly obovoid, 1–1.6(–1.8) × 0.4–0.6 mm, chalazal collar 0.1–0.2 mm, light brown or gray, surface rugose to papillose; coma usually readily detached, white, 3–9 mm.	(1 or) many per locule, with tuft of hairs (coma) at chalazal end, sometimes without coma.
2n	= 36.

	Epilobium saximontanum	Onagraceae tribe Epilobieae
Phenology	Flowering Jul–Sep.
Habitat	Montane semi-shaded stream banks, damp meadows, mossy seeps, wet slatey cliffs, disturbed or seasonally damp areas.
Elevation	0–3700 m. (0–12100 ft.)
Distribution	AZ; CA; CO; ID; MT; NM; NV; OR; SD; UT; WY; AB; BC; MB; NF; ON; QC [WildflowerSearch map] [BONAP county map]	North America; Mexico; Central America; South America; West Indies; Eurasia; Africa; Atlantic Islands; Australasia [Introduced in Pacific Islands]
Discussion	Epilobium saximontanum is morphologically similar to E. ciliatum (especially subsp. glandulosum) with which it also shares the AA chromosome arrangement. However, in addition to its fleshy compact turions, it very characteristically has notably appressed capsules, unlike most other species in the genus, and a notably strict habit. The distribution of Epilobium saximontanum is unusual; it includes the Rocky Mountain region, only barely reaching the high southern Sierra Nevada, disjunct to the Black Hills of South Dakota, and more widely in eastern Canada, from the shores of Hudson Bay to Newfoundland. Specimens are fairly uniform across this wide and rather discontinuous range, although locally they show some variability, possibly due to hybridization with any of several species that may be sympatric with it. H. Lewis and D. M. Moore (1962) reported hybrids between E. saximontanum (cited as E. brevistylum) and E. ciliatum subsp. ciliatum (cited as E. adenocaulon) from Colorado, and herbarium specimens with E. saximontanum and apparent hybrids are not uncommon. (Discussion copyrighted by Flora of North America; reprinted with permission.)	Genera 2, species 173 (2 genera, 43 species in the flora). Epilobium and its close relatives have been recognized historically either as part of Onagreae (A. P. de Candolle 1828b), sometimes as a subtribe (É. Spach 1834–1848, vol. 4; J. Torrey and A. Gray 1838–1843, vol. 1), or as the distinct Epilobieae (R. Raimann 1893; P. A. Munz 1965; P. H. Raven 1976). The synapomorphies for Epilobieae as currently delimited include its highly condensed, heteropycnotic chromosomes with a base chromosome number of x = 18, sepals held erect or spreading (not reflexed) throughout anthesis, and the presence of a coma of hairs on the seeds (secondarily lost in some species). Molecular support for the tribe is strong (97–100% BOOTSTRAP support; D. A. Baum et al. 1994; R. A. Levin et al. 2004). Endlicher established Epilobieae and included Oenothera within it; it is unclear how or whether his concept differed from Onagreae of A. P. de Candolle (1828b). É. Spach (1834–1848, vol. 4) recognized these genera as Onagreae and differentiated so-called sect. Oenotherinae from sect. Epilobieae, placing in the latter not only Epilobium and related groups, but also Clarkia and its segregates. J. Torrey and A. Gray (1840) excluded Clarkia from their Epilobiinae and also excluded Boisduvalia, a delimitation also followed by R. Raimann (1893) for his Epilobieae. Epilobieae did not assume its current delimitation, including only Epilobium and its close relatives, until the works of P. A. Munz (1941) and P. H. Raven (1964). G. L. Stebbins (1971) and P. H. Raven (1976) considered the diverse chromosome numbers in Epilobieae and proposed that the species of Boisduvalia (now a section of Epilobium) with n = 9 or 10 represented the original base chromosome number for the tribe, and that these numbers were derived from x = 11 which is found in Circaeeae, Gongylocarpeae, and Lopezieae (W. L. Wagner et al. 2007). They proposed a series of aneuploid reductions from n = 9 or 10 to n = 6, followed by polyploidy to produce the array of numbers in Epilobium (n = 12, 13, 15, 16, 18, 30) and Boisduvalia (n = 9, 10, 15, 19). D. A. Baum et al. (1994) demonstrated that molecular data did not support that hypothesis and found that a monophyletic Chamaenerion (n = 18, 36, 54) forms a strongly distinct sister branch to Epilobium, within which sect. Epilobium (n = 18) is monophyletic and sister to the rest of Epilobium, including the former segregates Boisduvalia and Zauschneria. The data from Baum et al. suggested that Epilobieae are primitively polyploid, with numbers based on x = 18, which is unique in the family. Using comparable sampling and some additional genes, R. A. Levin et al. (2004) found strong support for the phylogeny proposed by Baum et al. (Discussion copyrighted by Flora of North America; reprinted with permission.)
Source	FNA vol. 10.	FNA vol. 10.
Parent taxa	Onagraceae > subfam. Onagroideae > tribe Epilobieae > Epilobium > sect. Epilobium	Onagraceae > subfam. Onagroideae
Sibling taxa	E. anagallidifolium, E. arcticum, E. brachycarpum, E. campestre, E. canum, E. ciliatum, E. clavatum, E. cleistogamum, E. coloratum, E. davuricum, E. densiflorum, E. densum, E. foliosum, E. glaberrimum, E. hallianum, E. hirsutum, E. hornemannii, E. howellii, E. lactiflorum, E. leptocarpum, E. leptophyllum, E. luteum, E. minutum, E. mirabile, E. montanum, E. nevadense, E. nivium, E. obcordatum, E. obscurum, E. oreganum, E. oregonense, E. pallidum, E. palustre, E. parviflorum, E. rigidum, E. septentrionale, E. siskiyouense, E. smithii, E. suffruticosum, E. torreyi
Subordinate taxa
Synonyms	E. adenocaulon subsp. rubescens, E. drummondii, E. drummondii var. latiusculum, E. latiusculum, E. ovatifolium, E. rubescens, E. scalare, E. stramineum	Epilobioideae alph., Boisduvaliinae raimann, Epilobiinae torrey
Name authority	Haussknecht: Oesterr. Bot. Z. 29: 119. (1879)	Endlicher: Fl. Poson., 366. (1830)
Web links	Local floras: BC, CA, OR Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Google search

Onagraceae tribe Epilobieae

glandular willowherb, Rocky Mountain willowherb, Rocky Mountain willowweed, épilobe des rocheuses

Habit

Herbs usually with sessile, fleshy, underground turions, or sometimes thick, elongated shoots with dark, decussate scales.

Herbs, annual or perennial, sometimes suffrutescent.

Stems

erect, strict, terete, 4–55 cm, simple or well branched in age, subglabrous proximally to mixed strigillose and glandular puberulent distally, with raised strigillose lines decurrent from margins of petioles.

Leaves

opposite proximal to inflorescence, alternate and reduced distally, often ± appressed, usually subsessile, rarely petiole 1–3 mm, often clasping;

blade obovate proximally to ovate, lanceolate, or narrowly elliptic distally, 1–5.5(–6.5) × 0.4–2(–2.4) cm, base rounded or obtuse, margins low denticulate, 9–30 teeth per side, veins ± conspicuous, 3–6 per side, apex subacute, surfaces subglabrous with strigillose margins;

bracts much reduced.

opposite at least near base or throughout, alternate distally, or sometimes alternate throughout;

stipules absent.

Inflorescences

erect, sometimes nodding in bud, racemes, sometimes sparsely branched.

Flowers

erect;

buds 2–3.5 × 1.8–2.5 mm;

pedicel 0–1 mm;

floral tube 0.8–1.4 × 0.8–1.9 mm, ring of sparse spreading hairs at mouth inside;

sepals sometimes flushed red, 1.2–3.5 × 0.6–1.4 mm, abaxial surface strigillose and sometimes mixed glandular puberulent;

petals usually white, infrequently pink, 2.2–5(–7) × 1.7–3.2 mm, apical notch 0.4–1.5 mm;

filaments usually cream, rarely light pink, those of longer stamens 2–3.5 mm, those of shorter ones 1–2 mm;

anthers cream to light yellow, 0.3–0.8 × 0.3–0.5 mm;

ovary 9–30 mm, densely strigillose and glandular puberulent;

style cream or yellow, 1.6–2.8 mm, stigma usually narrowly to broadly clavate, rarely subcapitate, 1–3 × 0.8–2 mm, surrounded by at least longer anthers.

actinomorphic or slightly zygomorphic, 4-merous;

sepals erect or spreading;

stamens 2 times as many as sepals;

pollen shed in tetrads or monads.

Fruit

a slender, cylindrical, loculicidal capsule.

Capsules

30–55(–70) mm, surfaces mixed strigillose and glandular puberulent; usually subsessile, rarely pedicel 1–5 mm, often appressed to stem.

Seeds

very narrowly obovoid, 1–1.6(–1.8) × 0.4–0.6 mm, chalazal collar 0.1–0.2 mm, light brown or gray, surface rugose to papillose;

coma usually readily detached, white, 3–9 mm.

(1 or) many per locule, with tuft of hairs (coma) at chalazal end, sometimes without coma.

= 36.

Epilobium saximontanum

Onagraceae tribe Epilobieae

Phenology

Flowering Jul–Sep.

Habitat

Montane semi-shaded stream banks, damp meadows, mossy seeps, wet slatey cliffs, disturbed or seasonally damp areas.

Elevation

0–3700 m. (0–12100 ft.)

Distribution

AZ; CA; CO; ID; MT; NM; NV; OR; SD; UT; WY; AB; BC; MB; NF; ON; QC

[WildflowerSearch map]

[BONAP county map]

North America; Mexico; Central America; South America; West Indies; Eurasia; Africa; Atlantic Islands; Australasia [Introduced in Pacific Islands]

Discussion

Epilobium saximontanum is morphologically similar to E. ciliatum (especially subsp. glandulosum) with which it also shares the AA chromosome arrangement. However, in addition to its fleshy compact turions, it very characteristically has notably appressed capsules, unlike most other species in the genus, and a notably strict habit.

The distribution of Epilobium saximontanum is unusual; it includes the Rocky Mountain region, only barely reaching the high southern Sierra Nevada, disjunct to the Black Hills of South Dakota, and more widely in eastern Canada, from the shores of Hudson Bay to Newfoundland. Specimens are fairly uniform across this wide and rather discontinuous range, although locally they show some variability, possibly due to hybridization with any of several species that may be sympatric with it. H. Lewis and D. M. Moore (1962) reported hybrids between E. saximontanum (cited as E. brevistylum) and E. ciliatum subsp. ciliatum (cited as E. adenocaulon) from Colorado, and herbarium specimens with E. saximontanum and apparent hybrids are not uncommon.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Genera 2, species 173 (2 genera, 43 species in the flora).

Epilobium and its close relatives have been recognized historically either as part of Onagreae (A. P. de Candolle 1828b), sometimes as a subtribe (É. Spach 1834–1848, vol. 4; J. Torrey and A. Gray 1838–1843, vol. 1), or as the distinct Epilobieae (R. Raimann 1893; P. A. Munz 1965; P. H. Raven 1976). The synapomorphies for Epilobieae as currently delimited include its highly condensed, heteropycnotic chromosomes with a base chromosome number of x = 18, sepals held erect or spreading (not reflexed) throughout anthesis, and the presence of a coma of hairs on the seeds (secondarily lost in some species). Molecular support for the tribe is strong (97–100% BOOTSTRAP support; D. A. Baum et al. 1994; R. A. Levin et al. 2004).

Endlicher established Epilobieae and included Oenothera within it; it is unclear how or whether his concept differed from Onagreae of A. P. de Candolle (1828b). É. Spach (1834–1848, vol. 4) recognized these genera as Onagreae and differentiated so-called sect. Oenotherinae from sect. Epilobieae, placing in the latter not only Epilobium and related groups, but also Clarkia and its segregates. J. Torrey and A. Gray (1840) excluded Clarkia from their Epilobiinae and also excluded Boisduvalia, a delimitation also followed by R. Raimann (1893) for his Epilobieae. Epilobieae did not assume its current delimitation, including only Epilobium and its close relatives, until the works of P. A. Munz (1941) and P. H. Raven (1964).

G. L. Stebbins (1971) and P. H. Raven (1976) considered the diverse chromosome numbers in Epilobieae and proposed that the species of Boisduvalia (now a section of Epilobium) with n = 9 or 10 represented the original base chromosome number for the tribe, and that these numbers were derived from x = 11 which is found in Circaeeae, Gongylocarpeae, and Lopezieae (W. L. Wagner et al. 2007). They proposed a series of aneuploid reductions from n = 9 or 10 to n = 6, followed by polyploidy to produce the array of numbers in Epilobium (n = 12, 13, 15, 16, 18, 30) and Boisduvalia (n = 9, 10, 15, 19). D. A. Baum et al. (1994) demonstrated that molecular data did not support that hypothesis and found that a monophyletic Chamaenerion (n = 18, 36, 54) forms a strongly distinct sister branch to Epilobium, within which sect. Epilobium (n = 18) is monophyletic and sister to the rest of Epilobium, including the former segregates Boisduvalia and Zauschneria. The data from Baum et al. suggested that Epilobieae are primitively polyploid, with numbers based on x = 18, which is unique in the family. Using comparable sampling and some additional genes, R. A. Levin et al. (2004) found strong support for the phylogeny proposed by Baum et al.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source

FNA vol. 10.

Parent taxa

Onagraceae > subfam. Onagroideae > tribe Epilobieae > Epilobium > sect. Epilobium

Onagraceae > subfam. Onagroideae

Sibling taxa

E. anagallidifolium, E. arcticum, E. brachycarpum, E. campestre, E. canum, E. ciliatum, E. clavatum, E. cleistogamum, E. coloratum, E. davuricum, E. densiflorum, E. densum, E. foliosum, E. glaberrimum, E. hallianum, E. hirsutum, E. hornemannii, E. howellii, E. lactiflorum, E. leptocarpum, E. leptophyllum, E. luteum, E. minutum, E. mirabile, E. montanum, E. nevadense, E. nivium, E. obcordatum, E. obscurum, E. oreganum, E. oregonense, E. pallidum, E. palustre, E. parviflorum, E. rigidum, E. septentrionale, E. siskiyouense, E. smithii, E. suffruticosum, E. torreyi

Subordinate taxa

Synonyms

E. adenocaulon subsp. rubescens, E. drummondii, E. drummondii var. latiusculum, E. latiusculum, E. ovatifolium, E. rubescens, E. scalare, E. stramineum

Epilobioideae alph., Boisduvaliinae raimann, Epilobiinae torrey

Name authority

Haussknecht: Oesterr. Bot. Z. 29: 119. (1879)

Endlicher: Fl. Poson., 366. (1830)

Web links

Local floras: BC, CA, OR
Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria
WildflowerSearch
iNaturalist (observations)
USDA Plants Database
LBJ Wildflower Center
SEINet
Plants of the World Online
Encyclopedia of Life
Wikipedia
Google Image Search

Google search

Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).

Choose a data source: Flora of North America, OregonFlora

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Epilobium saximontanum

Onagraceae tribe Epilobieae

Epilobium saximontanum

Onagraceae tribe Epilobieae